Power generated by generating equipment is usually delivered in the form of an alternating current to a load by using a distribution system. The power supply function of the distribution system is implemented by using distribution feeders. Therefore, if a distribution feeder in the distribution system has a broken conductor, the distribution system fails, and cannot supply power normally. To make sure that the distribution system supplies power normally, a broken conductor detection technology needs to be used so that a broken conductor of a distribution feeder can be detected when it appears in the distribution system.
At present, the negative phase sequence current detection method is widely used to detect whether a distribution feeder in a distribution system has a broken conductor. In the negative phase sequence current detection method, a negative phase sequence current and a positive phase sequence current of the distribution feeder are first detected, and then a ratio of the detected negative phase sequence current to the detected positive phase sequence current is calculated; after that, it is determined whether the calculated ratio is greater than a constant (generally 50%). and if yes, it is considered that the distribution feeder has a broken conductor.
It can be seen that, the negative phase sequence current detection method is highly dependent on a current flowing through a distribution feeder during the broken conductor detection. However, in some cases of a broken conductor of a distribution feeder, for example, if the broken conductor of the feeder is lying on a highly resistive surface of a paved road or if the feeder having the broken conductor, which appears at the end of the distribution system, hangs in the air. no current (neither negative phase sequence current nor a positive phase sequence current) flows through me distribution feeder. Therefore, the negative phase sequence current detection method is not applicable to detect all conductor-broken situations of distribution feeders. In addition, the negative phase sequence current detection method cannot locate the broken conductor of the distribution feeder either.